He got 14 boards and 4 assists (as you can check in espn, sofascore, google and many other box scores) yet the game counted 6 boards and 1 assist. We are currently in playoffs, than many points can change the outcome of an important game.

The Sports.ws stats pull directly from NBA.com.

According to NBA.com (and ESPN and Basketball Reference), Wendell Carter registered 9 points, 6 rebounds and 1 assist in Game 60 (Feb. 25).

In Game 61 he registered 9 points, 14 rebounds and 4 assists (Feb. 27), maybe that's what you're seeing.

Good luck in the playoffs!